i suppose the obvious is that IRL you drive with a certain fear, to crash, die, do something else terrible.
in a sim who cares if you crash- unless you understand real racing, than you wouldn't. as said a post ago, you drive over the limit and bring it with in the limits i a SIM, not IRL.
Many people drive sims and have never driven in real life, so they do not bring track conduct and etiquette into the online world, as if the rules are different

lets face it 3 or 33 laps, the race still is most fun when everyone can finish intact, so why would you wreck and make foolish passes or attempts if you may sacrfice the race for you or others?
it is noobish and rude,
racing on STCC,(mostly better than silver license) the much faster guys occasionally get a little impatient, but most STCC racers do wait for an opportunity to pass, rather than force it.
CORE-racing is the same, just good racing. which means not wrecking int T1 and not trying to pass in a chicane (Fernbay anyone?), which wreckers and schmucks seem to think there is more than one line in.